Serum Perfluoroalkyl Substances Concentrations Research Articles

Maternal serum concentrations of perfluoroalkyl substances and birth size in British boys.

Per- and polyfluoroalkyl substances (PFAS) have been widely used in commercial and industrial manufacturing processes since the 1950s. Inverse associations between prenatal exposure to PFAS and birth size have been found in populations around the globe. This study examined the association of prenatal maternal serum concentrations of perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorohexane sulfonic acid (PFHxS), and perfluorononanoic acid (PFNA) and birth size in British boys. The study included 457 mother-son dyads participating in the Avon Longitudinal Study of Parents and Children (ALSPAC). Birth weight (g), crown to heel length (cm), and head circumference (cm) were collected at delivery. PFAS were detected in all maternal serum samples during pregnancy (median: 30 weeks gestation (interquartile range: 12-33)). Median concentrations (interquartile range) were 13.8 ng/mL (11.0, 17.7), 3.0 ng/mL (2.3, 3.8), 1.9 ng/mL (1.4, 2.5), and 0.4 ng/mL (0.3, 0.5) for PFOS, PFOA, PFHxS, and PFNA, respectively. In multivariable linear regression models, inverse associations were detected between PFOS (continuous) and birth weight (β = -8.50 g, 95% CI = -15.93, -1.07 g), crown to heel length (β = -0.04 cm, 95% CI = -0.08, -0.01 cm), and head circumference (β = -0.02 cm, 95% CI = -0.04, -0.002 cm). In conclusion, prenatal exposure to high levels of PFOS may be associated with reduced birth size in male infants.

Selective Associations of Recent Low Concentrations of Perfluoroalkyl Substances With Liver Function Biomarkers: NHANES 2011 to 2014 Data on US Adults Aged ≥20 Years.

Perfluoroalkyl substances (PFAS) and liver function biomarkers were reexamined for relatively lower serum concentrations of PFAS observed in recent years. National Health and Nutrition Examination Survey 2011 to 2014 data were analyzed for obese and nonobese participants for serum perfluorooctanoic acid (PFOA), perfluorooctane sulfonate (PFOS), perfluorodecanoic acid (PFDA), perfluorohexane sulfonate (PFHxS), perfluorononanoic acid (PFNA) as well as four liver function biomarkers in risk-adjusted analysis. Among obese participants only, alanine aminotransferase (ALT) was positively associated with PFOA (β = 0.07065, P < 0.01), PFHxS (β = 0.051349, P < 0.01), and with PFNA (β = 0.072742, P < 0.01). PFOA (β = 0.07422, P = 0.03) and PFNA (β = 0.077995, P < 0.01) were associated with gamma glutamyl transferase (GGT) in obese participants. Recent lower levels of PFOA, PFHxS, and PFNA are associated with higher serum liver functions but only among obese participants. The findings are consistent with PFAS animal toxicology concerning steatosis.

Health Status of Elderly People Living Near E-Waste Recycling Sites: Association of E-Waste Dismantling Activities with Legacy Perfluoroalkyl Substances (PFASs)

The elderly people living near electronic waste (e-waste) dismantling sites are susceptible to elevated chemical exposure, which is acerbated by hypometabolism and diminished immune tolerance. In this study, paired serum and urine samples collected from 1025 elderly people (≥60 years old) living near e-waste dismantling sites (n = 800) and reference areas (n = 225) in South China were analyzed for markers of health status and chemical exposures. Our results indicated that among all the health indicators fasting blood glucose (FBG) and urinary clinical markers were significantly higher in e-waste areas than in the reference area. Sixteen legacy perfluoroalkyl substances (PFASs) were determined in serum samples of elderly individuals living near e-waste dismantling areas (n = 171) and a reference area (n = 50). Serum PFASs concentrations in individuals from e-waste dismantling areas were significantly higher (p < 0.05) than those from the reference area, which indicated that e-waste dismantling activities a...

Assessment of individual-based perfluoroalkly substances exposure by multiple human exposure sources.

Individual exposure of perfluoroalkyl substances (PFASs) was assessed by analyzing serum, food, dust, drinking water, and hand wipes from 50 individuals. The PFASs concentrations in serum were correlated most strongly with exposure to PFASs through the (direct and indirect) ingestion of dust (p < 0.01). Daily PFOA intakes were estimated to be 2.07 ng/kg/day from food, 0.003 ng/kg/day from dust, 0.053 ng/kg/day from hand-to-mouth activity, and 0.020 ng/kg/day from drinking water. Daily perfluorooctanesulfonic acid (PFOS) intakes were estimated to be 0.689 ng/kg/day from food, 0.001 ng/kg/day from dust, 0.018 ng/kg/day from hand-to-mouth activity, and 0.005 ng/kg/day from drinking water. The daily PFOA and PFOS intakes calculated for individuals in this study and in group/scenario based exposure assessment of previous studies were compared. The estimated PFOS intake on individual basis (0.695 ng/kg/day) was a little bit higher than the intake on group/scenario basis (0.652 ng/kg/day). However, the estimated daily PFOA intake on individual basis (1.41 ng/kg/day) was about four times higher than the intake on group/scenario basis (0.339 ng/kg/day). Among the exposure pathways, food ingestion was major contributor to the total daily PFOA and PFOS intakes on individuals (99% of total intake) and group/scenario basis (64% of total intake).

Perfluoroalkyl substances and metabolic syndrome.

Perfluoroalkyl substances (PFAS) are a class of contaminants used in many industrial applications and consumer products. Certain PFAS are regulated or voluntarily limited due to concern about environmental persistence and adverse health effects. In this analysis we examine PFAS levels and their association with metabolic syndrome and its components, using a representative sample of the U.S. Data on PFAS levels and metabolic syndrome components were collected from the 2007-2008, 2009-2010, 2011-2012, and 2013-2014 cycles of the National Health and Nutrition Examination Survey. Twelve different PFAS were measured in serum samples from participants. Logistic regression models were used to identify associations between metabolic syndrome, its individual components, and serum PFAS concentrations. Over one-third (37%) of participants met the definition for metabolic syndrome, with increased waist circumference and elevated glucose being the most commonly reported components. Seven PFAS were detected in at least 30% of participants and were examined in subsequent analyses (PFDA, PFOA, PFOS, PFHxS, MPAH, PFNA, PFUnDA). The PFAS with the highest concentrations was PFOS (median 8.4 ng/mL), followed by PFOA, PFHxS and PFNA. After adjusting for potential confounders, PFNA was associated with increased risk of metabolic syndrome and well as several individual components, while the highest levels of PFHxS were associated with elevated triglycerides. Other PFAS were associated with decreased risk of at least one outcome. Associations between PFAS and metabolic syndrome are inconsistent within and across studies. PFNA was consistently associated with increased risk for components of the syndrome, a finding that warrants further investigation.

Childhood perfluoroalkyl substance exposure and executive function in children at 8 years

BackgroundToxicological studies highlight the potential neurotoxicity of perfluoroalkyl substances (PFAS) during fetal development. However, few epidemiological studies have examined the impact of childhood PFAS on neurodevelopment. MethodsWe employed data from 208 children in the Health Outcomes and Measures of the Environment Study, a birth cohort (Cincinnati, OH), to examine associations of six serum PFAS concentrations measured at 3 and 8 years with executive function assessed at 8 years using the validated parent-completed Behavior Rating Inventory of Executive Function survey. We used multiple informant models to identify susceptible windows of neurotoxicity to PFAS and executive function. We investigated trajectories of PFAS concentrations and whether sex modified these associations. ResultsEach ln-increase in perfluorononanoate (PFNA) at 8 years was associated with a 3.4-point increase (95% CI 0.4, 6.3) in metacognition score, indicating poorer function. Children with PFNA above the median at 8 years had poorer global executive functioning compared to children with concentrations consistently below median levels (β = 6.5, 95% CI 0.2, 12.9). Higher concurrent PFNA was associated with poorer behavior regulation among males, while associations among females were null (pPFNA×sex = 0.018). Children with higher concurrent perfluorooctanoate (PFOA) had increased odds of being at risk of having clinical impairments in metacognition (OR = 3.18, 95% CI 1.17, 8.60). There were no associations between perfluorooctane sulfonate and perfluorohexane sulfonate and executive function. ConclusionsPFNA and PFOA at 8 years, but not 3 years, may be related to poorer executive function at 8 years. Results need to be confirmed in cohort studies with larger sample sizes.

Variability and predictors of serum perfluoroalkyl substance concentrations during pregnancy and early childhood

Exposure to poly- and perfluoroalkyl substances (PFAS), ubiquitous and persistent environmental contaminants, could be associated with adverse health outcomes, but there are limited longitudinal data assessing patterns and predictors of exposure during childhood. We quantified concentrations of eight different PFAS in sera collected from women during pregnancy and children at delivery and ages 3 and 8 years in 367 mother-child pairs enrolled in a prospective cohort from 2003 to 2006. In general, median childhood PFAS concentrations increased from birth to age 3 and then decreased by age 8. Maternal serum PFAS concentrations during pregnancy were strongly correlated with cord serum concentrations (0.76 < r < 0.94), but were weakly correlated with childhood concentrations (0.12 < r < 0.30). Several sociodemographic factors were associated with maternal PFAS concentrations, including income, race, and parity. In children, serum PFAS concentrations were associated with maternal age at delivery, race, parity, and child age. Breastfeeding duration was positively associated with childhood PFAS concentrations at ages 3 and 8 years. In addition, stain repellant use was associated with higher perfluorooctanoic acid and perfluorohexane sulfonic acid concentrations at age 8 years. Serum PFAS concentrations are higher during early childhood, a potentially sensitive period of development, and were highest among breastfed children.

Perfluoroalkyl substances in adolescents in northern Norway: Lifestyle and dietary predictors. The Tromsø study, Fit Futures 1

Perfluoroalkyl substances (PFASs) are environmentally persistent chemicals widely used in many consumer products due to water and oil proofing and fire-resistant properties. Several PFASs are recognized as environmental pollutants. This study investigated serum concentrations of 18 different PFASs and their associations with diet and lifestyle variables in 940 adolescents (age 15–19 years) who participated in the Fit Futures 1 study in the Troms arctic district of Norway. Serum concentrations of PFASs were analyzed by ultrahigh pressure liquid chromatography coupled to a triple quadrupole mass spectrometer (UHPLC-MS/MS). The most abundant PFASs in this population were perfluorooctane sulfonate (PFOS), perfluorooctanoate (PFOA), perfluorohexane sulfonate (PFHxS), perfluorononanoate (PFNA) and perfluorodecanoate (PFDA) that were found in 99% of the participants. Perfluoroheptane sulfonate (PFHpS) was found in 98% of the participants. Median concentrations were: PFOS 6.20 ng/mL, PFOA 1.92 ng/mL, PFHxS 0.71 ng/mL, PFNA 0.50 ng/mL, PFDA 0.21 ng/mL and PFHpS 0.15 ng/mL. Median of PFASs sum concentration (∑PFAS) was 10.7 ng/mL, the concentration range was 2.6–200.8 ng/mL. Intake of fat fish, fish liver, seagull eggs, reindeer meat and drinks with sugar were the main dietary predictors of several PFASs. Intake of junk food (pizza, hamburger, sausages) was positively associated with PFNA, intake of canned food was positively associated with PFHxS. Intake of fruits and vegetables, milk products, snacks and candy was not associated with PFASs concentrations. Lean fish intake was positively associated with PFUnDA, but not with other PFASs. There was a positive association of ∑PFAS, PFHxS, PFOA, PFNA and PFDA with chewed tobacco use.

Can profiles of poly- and Perfluoroalkyl substances (PFASs) in human serum provide information on major exposure sources?

BackgroundHumans are exposed to poly- and perfluoroalkyl substances (PFASs) from diverse sources and this has been associated with negative health impacts. Advances in analytical methods have enabled routine detection of more than 15 PFASs in human sera, allowing better profiling of PFAS exposures. The composition of PFASs in human sera reflects the complexity of exposure sources but source identification can be confounded by differences in toxicokinetics affecting uptake, distribution, and elimination. Common PFASs, such as perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS) and their precursors are ubiquitous in multiple exposure sources. However, their composition varies among sources, which may impact associated adverse health effects.MethodsWe use available PFAS concentrations from several demographic groups in a North Atlantic seafood consuming population (Faroe Islands) to explore whether chemical fingerprints in human sera provide insights into predominant exposure sources. We compare serum PFAS profiles from Faroese individuals to other North American populations to investigate commonalities in potential exposure sources. We compare individuals with similar demographic and physiological characteristics and samples from the same years to reduce confounding by toxicokinetic differences and changing environmental releases.ResultsUsing principal components analysis (PCA) confirmed by hierarchical clustering, we assess variability in serum PFAS concentrations across three Faroese groups. The first principal component (PC)/cluster consists of C9-C12 perfluoroalkyl carboxylates (PFCAs) and is consistent with measured PFAS profiles in consumed seafood. The second PC/cluster includes perfluorohexanesulfonic acid (PFHxS) and the PFOS precursor N-ethyl perfluorooctane sulfonamidoacetate (N-EtFOSAA), which are directly used or metabolized from fluorochemicals in consumer products such as carpet and food packaging. We find that the same compounds are associated with the same exposure sources in two North American populations, suggesting generalizability of results from the Faroese population.ConclusionsWe conclude that PFAS homologue profiles in serum provide valuable information on major exposure sources. It is essential to compare samples collected at similar time periods and to correct for demographic groups that are highly affected by differences in physiological processes (e.g., pregnancy). Information on PFAS homologue profiles is crucial for attributing adverse health effects to the proper mixtures or individual PFASs.

Prenatal exposure to persistent organic pollutants and child overweight/obesity at 5-year follow-up: a prospective cohort study

BackgroundPrenatal exposure to persistent organic pollutants (POPs), may influence offspring weight gain. More prospective epidemiological studies are needed to compliment the growing body of evidence from animal studies.MethodsSerum from 412 pregnant Norwegian and Swedish women participating in a Scandinavian prospective cohort study were collected in 1986–88, and analyses of two perfluoroalkyl substances (PFASs) and five organochlorines (OCs) were conducted. We used linear and logistic regression models with 95% confidence intervals (CIs) to evaluate the associations between maternal serum POP concentrations at 17–20 weeks of gestation and child overweight/obesity (body mass index (BMI) ≥ 85th percentile) at 5-year follow-up. Results were further stratified by country after testing for effect modification. We also assessed potential non-monotonic dose-response (NMDR) relationships.ResultsIn adjusted linear models, we observed increased BMI-for-age-and-sex z-score (β = 0.18, 95% CI: 0.01–0.35), and increased triceps skinfold z-score (β = 0.15, 95% CI: 0.02–0.27) in children at 5-year follow-up per ln-unit increase in maternal serum perfluorooctane sulfonate (PFOS) concentrations. We observed increased odds for child overweight/obesity (BMI ≥ 85th percentile) for each ln-unit increase in maternal serum PFOS levels (adjusted OR: 2.04, 95% CI: 1.11–3.74), with stronger odds among Norwegian children (OR: 2.96, 95% CI: 1.42–6.15). We found similar associations between maternal serum perfluorooctanoate (PFOA) concentrations and child overweight/obesity. We found indications of NMDR relationships between PFOS and polychlorinated biphenyl (PCB) 153 and child overweight/obesity among Swedish children.ConclusionWe found positive associations between maternal serum PFAS concentrations and child overweight/obesity at 5-year follow-up, particularly among Norwegian participants. We observed some evidence for NMDR relationships among Swedish participants.

Prenatal and childhood perfluoroalkyl substances exposures and children's reading skills at ages 5 and 8 years

BackgroundExposure to perfluoroalkyl substances (PFASs) may impact children's neurodevelopment. ObjectiveTo examine the association of prenatal and early childhood serum PFAS concentrations with children's reading skills at ages 5 and 8years. MethodsWe used data from 167 mother-child pairs recruited during pregnancy (2003–2006) in Cincinnati, OH, quantified prenatal serum PFAS concentrations at 16±3weeks of gestation and childhood sera at ages 3 and 8years. We assessed children's reading skills using Woodcock-Johnson Tests of Achievement III at age 5years and Wide Range Achievement Test-4 at age 8years. We used general linear regression to quantify the covariate-adjusted associations between natural log-transformed PFAS concentrations and reading skills, and used multiple informant model to identify the potential windows of susceptibility. ResultsMedian serum PFASs concentrations were PFOS>PFOA>PFHxS>PFNA in prenatal, 3-year, and 8-year children. The covariate-adjusted general linear regression identified positive associations between serum PFOA, PFOS and PFNA concentrations and children's reading scores at ages 5 and 8years, but no association between any PFHxS concentration and reading skills. The multiple informant model showed: a) Prenatal PFOA was positively associated with higher children's scores in Reading Composite (β: 4.0, 95% CI: 0.6, 7.4 per a natural log unit increase in exposure) and Sentence Comprehension (β: 4.2, 95% CI: 0.5, 8.0) at age 8years; b) 3-year PFOA was positively associated with higher children's scores in Brief Reading (β: 7.3, 95% CI: 0.9, 13.8), Letter Word Identification (β: 6.6, 95% CI: 1.1, 12.0), and Passage Comprehension (β: 5.9, 95% CI: 1.5, 10.2) at age 5years; c) 8-year PFOA was positively associated with higher children's Word Reading scores (β: 5.8, 95% CI: 0.8, 10.7) at age 8years. Prenatal PFOS and PFNA were positively associated with children's reading abilities at age 5years, but not at age 8years; 3-year PFOS and PFNA were positively associated with reading scores at age 5years. But PFHxS concentrations, at any exposure windows, were not associated with reading skills. ConclusionPrenatal and childhood serum PFOA, PFOS and PFNA concentrations were positively associated with better children's reading skills at ages 5 and 8years, but no association was found between serum PFHxS and reading skills.

Perfluoroalkyl substance exposure and urine CC16 levels among asthmatics: A case–control study of children

BackgroundStudies have reported an association between serum perfluoroalkyl substances (PFASs) and asthma. However, few studies have examined the possible associations between PFASs and the 16-kDa club cell secretory protein (Clara) (CC16) level, a prominent biomarker of asthma, among adolescents. MethodsWe recruited a total of 231 asthmatic children and 225 non-asthmatic controls in the Genetic and Biomarkers study for Childhood Asthma (GBCA) in northern Taiwan from 2009 to 2010. Structured questionnaires were administered by face-to-face interview. Urine CC16 was determined by an enzyme-link immunoassay kit. Multiple general linear models were employed to examine the associations between PFASs and urinary CC16 levels. ResultsAsthmatic participants had significantly higher serum PFAS concentrations overall than the healthy controls. After adjusting for confounding factors, urinary CC16 was significantly, negatively associated with PFASs, especially PFOS, PFOA, PFDA and PFNA, and especially among males, as follows: PFOS (β = −0.003, 95% confidence interval [CI]: −0.004, −0.002), PFOA (β = −0.045, 95% CI: −0.086, −0.004), and PFHxA (β = −0.310, 95% CI: −0.455, −0.165) among asthmatic boys, and PFDA (β = −0.126, 95%CI: −0.241, −0.012) and PFNA (β = −0.329, 95% CI: −0.526, −0.132) among non-asthmatic boys. Among girls, PFDA (β = −0.088, 95% CI: −0.172, −0.004), was the only PFAS significantly associated with CC16. Significant interaction effects (p < 0.15) on CC16 levels were found between asthma and PFOS, PFOA, PFBS and PFHxA in all participants. ConclusionOur overall results showed that serum PFASs were significantly, inversely associated with CC16 levels. Associations were stronger among males.

Association of perfluoroalkyl substances exposure with impaired lung function in children

Previous studies have demonstrated associations between serum levels of perfluoroalkyl substances (PFASs) and asthma or asthma related-biomarkers. However, no studies have reported a possible relationship between PFASs exposure and lung function among children. The objective of the present study is to test the association between PFASs exposure and lung function in children from a high exposure area by using a cross-sectional case-control study, which included 132 asthmatic children and 168 non-asthmatic controls recruited from 2009 to 2010 in the Genetic and Biomarkers study for Childhood Asthma. Structured questionnaires were administered face-to-face. Lung function was measured by spirometry. Linear regression models were used to examine the influence of PFASs on lung function. The results showed that asthmatics in our study had significantly higher serum PFAS concentrations than healthy controls. Logistic regression models showed a positive association between PFASs and asthma, with adjusted odds ratios (ORs) ranging from 0.99 (95% confidence interval [CI]: 0.80–1.21) to 2.76 (95% CI: 1.82–4.17). Linear regression modeling showed serum PFASs levels were significantly negatively associated with three pulmonary function measurements (forced vital capacity: FVC; forced expiratory volume in 1s: FEV1; forced expiratory flow 25–75%: FEF25–75) among children with asthma, the adjusted coefficients between lung function and PFASs exposure ranged from −0.055 (95%CI: −0.100 to −0.010) for FVC and perfluorooctane sulfonate (PFOS) to −0.223 (95%CI: −0.400 to −0.045) for FEF25–75 and perfluorooctanoic acid (PFOA). PFASs were not, however, significantly associated with pulmonary function among children without asthma. In conclusion, this study suggests that serum PFASs are associated with decreased lung function among children with asthma.

Quantitative bias analysis for epidemiological associations of perfluoroalkyl substance serum concentrations and early onset of menopause

An association between increased serum concentrations of perfluoroalkyl substances (PFAS) such as perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) and early menopause has been reported (Knox et al., 2011; Taylor et al., 2014). This association may be explained by the fact that women who underwent menopause no longer excrete PFAS through menstruation. Our objective was to assess how much of the epidemiologic association between PFAS and altered timing of menopause might be explained by reverse causality. We extended a published population life-stage physiologically-based pharmacokinetic (PBPK) model of PFOS and PFOA characterized by realistic distributions of physiological parameters including age at menopause. We then conducted Monte Carlo simulations to replicate the Taylor population (Taylor et al., 2014) and the Knox population (Knox et al., 2011). The analysis of the simulated data overall showed a pattern of results that was comparable to those reported in epidemiological studies. For example, in the simulated Knox population (ages 42–51) the odds ratio (OR) for menopause in the fifth quintile of PFOA compared to those in the first quintile was 1.33 (95% CI 1.26–1.40), whereas the reported OR was 1.4 (95% CI 1.1–1.8). Using our model structure, a substantial portion of the associations reported can be explained by pharmacokinetics.

Shorter duration of breastfeeding at elevated maternal serum concentrations of perfluoroalkyl substances

Introduction: Breastfeeding has a number of positive effects on the infant as well as the mother, but globally only 38% of infants are exclusively breastfed for six months as recommended by the Wor...

Circulating levels of perfluoroalkyl substances are associated with dietary patterns – A cross sectional study in elderly Swedish men and women

BackgroundIn our daily life, we are exposed to perfluoroalkyl substances (PFAS) with possible health implications. The main exposure route for these substances is diet but comparative studies on how dietary habits influence exposure are lacking. ObjectivesTo examine the relations between blood levels of PFAS and adherence to three predefined dietary patterns (a WHO recommended diet, a Mediterranean-like diet, and a Low-Carbohydrate High-Protein (LCHP) diet) in an elderly Swedish population. MethodsDietary data from 7-day food records and serum concentrations of PFAS were obtained from a 70-year-old Swedish population (n=844), the Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) study. The Healthy Diet Indicator score (based on WHO recommendations), the Mediterranean Diet Score and LCHP score were used to assess adherence. Multivariate linear regression was used to assess the associations between eight major PFAS and adherence to each dietary pattern. ResultsThe WHO recommended diet was positively associated with perfluorohexane sulfonic acid (PFHxS). The LCHP diet was positively related to four out of eight PFAS; namely, perfluorooctane sulfonic acid (PFOS), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA) and perfluoroundecanoic acid (PFUnDA). The Mediterranean-like diet was positively associated with most PFAS; namely perfluorooctanoic acid (PFOA), perfluorooctane sulfonamide (PFOSA), PFHxS, PFNA, PFDA, and PFUnDA. ConclusionsAll dietary patterns were positively associated with blood levels of PFAS. The highest body burden of PFAS was found in individuals with high adherence to a Mediterranean-like diet, whilst individuals who more closely followed the officially recommended diet displayed a lower body burden of these compounds.

Perfluoroalkyl Substances In Matched Maternal-Cord Samples From A Birth Cohort

Introduction: Prenatal exposure to perfluoroalkyl substances (PFAS) may affect child growth; thus estimating PFAS fetal body burden is relevant. PFAS fetal burden is considered best estimated in cord samples; however previous cohort studies have used either maternal plasma or serum indistinctively during pregnancy as proxy. We evaluated the correlations and the transfer ratio between PFAS concentration in maternal plasma and serum in pregnancy, and cord serum at birth in a Spanish birth cohort. Methods: We measured perfluorobutanesulfonic acid (PFBS), perfluorohexanesulfonic acid (PFHxS), perfluorooctanesulfonic acid (PFOS), perfluorooctanoic acid (PFOA), and perfluorononanoic acid (PFNA) in 67 mother-child pairs. We assessed the correlations between PFAS concentrations in first trimester maternal plasma and serum, with cord serum samples using the Spearman's rank coefficients. We evaluated PFAS transfer from mother to fetus using maternal to cord ratios. Results: Median concentrations (ng/mL) of PFHxS, PFOS, PFOA, and PFNA in maternal plasma (0.76, 6.14, 2.82 and 0.84, respectively) and serum (0.84, 6.73, 3.14 and 0.86) were higher than in cord serum (0.40, 1.87, 1.90 and 0.33). PFBS was not detected. Strong positive correlations (p-values

Transfer of perfluoroalkyl substances from mother to fetus in a Spanish birth cohort

IntroductionPrenatal exposure to perfluoroalkyl substances (PFAS) might affect child health; thus estimating PFAS fetal burden is relevant. PFAS fetal burden is best estimated in cord samples; previous studies have used either maternal plasma or serum during pregnancy as proxy, but their validity is not clear. We aimed to evaluate PFAS transfer between mother and fetus and determine its predictors in a Spanish birth cohort. MethodsWe measured perfluorobutane sulfonate (PFBS), perfluorohexane sulfonate (PFHxS), perfluorooctane sulfonate (PFOS), perfluorooctanoate (PFOA), and perfluorononanoate (PFNA) in maternal blood and cord serum from 66 mother–child pairs. We used Spearman's rank coefficients to correlate PFAS concentrations in first trimester maternal plasma and serum, with cord serum samples. We assessed PFAS placental transfer by calculating maternal to cord ratios and examined their association with maternal socio-demographic characteristics and child sex using linear regression models. ResultsMedian concentrations of PFAS (ng/mL) of PFHxS, PFOS, PFOA, and PFNA in maternal plasma (0.79, 6.18, 2.85 and 0.84, respectively) and serum (0.84, 6.99, 2.97 and 0.85) were higher than in cord serum (0.40, 1.86, 1.90 and 0.32). PFBS was not detected. Positive Spearman’s correlations (p-values<0.001) were found between maternal plasma and serum (⍴≥0.80), maternal plasma and cord (⍴≥0.66), and maternal serum and cord samples (⍴≥0.67). Maternal plasma to cord ratios were above 1 (PFHxS: 2.35 [95%CI: 2.05, 2.70], PFOS: 3.33 [3.05, 3.62], PFOA: 1.37 [1.27, 1.48], PFNA: 2.39 [2.18, 2.63]); maternal serum to cord ratios were similar. Maternal to cord ratios decreased with maternal age, but not with other socio-demographic factors. ConclusionsOur results suggest that PFAS fetal body burden can be assessed using as proxy maternal plasma or serum collected early in pregnancy. Maternal age might influence PFAS placental transfer.

Association of Perfluoroalkyl Substances, Bone Mineral Density, and Osteoporosis in the U.S. Population in NHANES 2009-2010.

BackgroundPerfluoroalkyl substances (PFASs), including perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS), perfluorohexane sulfonic acid (PFHxS), and perfluorononanoic acid (PFNA), are detectable in the serum of 95% of the U.S. population.ObjectiveConsidering the role of PFASs as endocrine disruptors, we examined their relationships with bone health.MethodsThe association between serum PFAS concentration and bone mineral density at total femur (TFBMD), femoral neck (FNBMD), lumbar spine (LSBMD), and physician-diagnosed osteoporosis was assessed in 1,914 participants using data from the National Health and Nutritional Examination Survey 2009–2010.ResultsThe mean age of the participants was 43 years. Men had higher serum PFAS concentrations than women (p < 0.001) except for PFNA. In both sexes, serum PFOS concentrations were inversely associated with FNBMD (p < 0.05). In women, significant negative associations were observed for natural log (ln)–transformed PFOS exposure with TFBMD and FNBMD, and for ln-transformed PFOA exposure with TFBMD (p < 0.05). In postmenopausal women, serum PFOS was negatively associated with TFBMD and FNBMD, and PFNA was negatively associated with TFBMD, FNBMD, and LSBMD (all p < 0.05). With one log unit increase in serum PFOA, PFHxS, and PFNA, osteoporosis prevalence in women increased as follows: [adjusted odds ratios (aORs)] 1.84 (95% CI: 1.17, 2.905), 1.64 (95% CI: 1.14, 2.38), and 1.45 (95% CI: 1.02, 2.05), respectively. In women, the prevalence of osteoporosis was significantly higher in the highest versus the lowest quartiles of PFOA, PFHxS, and PFNA, with aORs of 2.59 (95% CI: 1.01, 6.67), 13.20 (95% CI: 2.72, 64.15), and 3.23 (95% CI: 1.44, 7.21), respectively, based on 77 cases in the study sample.ConclusionIn a representative sample of the U.S. adult population, serum PFAS concentrations were associated with lower bone mineral density, which varied according to the specific PFAS and bone site assessed. Most associations were limited to women. Osteoporosis in women was also associated with PFAS exposure, based on a small number of cases.CitationKhalil N, Chen A, Lee M, Czerwinski SA, Ebert JR, DeWitt JC, Kannan K. 2016. Association of perfluoroalkyl substances, bone mineral density, and osteoporosis in the U.S. population in NHANES 2009–2010. Environ Health Perspect 124:81–87; http://dx.doi.org/10.1289/ehp.1307909

Can the observed association between serum perfluoroalkyl substances and delayed menarche be explained on the basis of puberty-related changes in physiology and pharmacokinetics?

BackgroundAn association between serum levels of two perfluoroalkyl substances (PFAS) and delayed age at menarche was reported in a cross-sectional study of adolescents. Because perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) have half-lives of years, growth dilution and the development of a new route of excretion (menstruation) could account for some or all of the reported association. ObjectivesTo assess how much of the epidemiologic association between PFAS and delayed menarche can be explained by the correlation of growth and maturation with PFAS body burden. MethodsWe developed a Monte Carlo (MC) physiologically-based pharmacokinetic (PBPK) model of PFAS to simulate plasma PFAS levels in a hypothetical female population aged 2 to 20years old. Realistic distributions of physiological parameters as well as timing of growth spurts and menarche were incorporated in the model. The association between PFAS level and delayed menarche in the simulated data was compared with the reported association. ResultsThe prevalence of menarche, distributions of age-dependent physiological parameters, and quartiles of serum PFAS concentrations in the simulated subjects were comparable to those reported in the epidemiologic study. The delay of menarche in days per natural log increase in PFAS concentrations in the simulated data were about one third as large as the observed values. ConclusionThe reported relationship between PFAS and age at menarche appears to be at least partly explained by pharmacokinetics rather than a toxic effect of these substances.